GridPP: the UK grid for particle physics.

The start-up of the Large Hadron Collider (LHC) at CERN, Geneva, presents a huge challenge in processing and analysing the vast amounts of scientific data that will be produced. The architecture of the worldwide grid that will handle 15 PB of particle physics data annually from this machine is based on a hierarchical tiered structure. We describe the development of the UK component (GridPP) of this grid from a prototype system to a full exploitation grid for real data analysis. This includes the physical infrastructure, the deployment of middleware, operational experience and the initial exploitation by the major LHC experiments.

Natural killer cytotoxic factor induction by K562 cells in patients with advanced cancer: correlation with production of interferon.

Advanced cancer patients were studied for their ability to produce natural killer cytotoxic factor (NKCF). Of 23 patients with advanced epithelial cancers, 8 showed deficient natural killer (NK) activity, as measured in a standard 51Cr release assay. Lymphocytes from these patients did not generate NKCF (nonproducers) in the presence of K562 cells. In addition, 7 other patients whose NK activity was in the normal range did not generate NKCF. Thus the deficiency in NKCF production was only partially correlated with the level of NK activity. Supernatants generated for NKCF were also assayed for antiviral activity. Mean interferon (IFN) titer of supernatants generated from peripheral blood lymphocytes (PBL) of cancer patients was significantly lower than that of supernatants generated by PBL from normal donors. Supernatants from 10 of 15 NKCF nonproducers contained no detectable IFN, whereas the remaining 5 contained up to 100 U IFN. NKCF was never generated in the absence of IFN. The defect in NKCF production by PBL from cancer patients could be corrected by the incubation of effector cells with exogenous IFN-alpha or IFN-alpha inducers, such as other tumor cells or viruses. The relationship among NKCF, IFN, and NK activities is discussed.

Human natural killer cytotoxic factor (NKCF): role of IFN-alpha.

The relationship between production of NKCF and IFN-alpha by human lymphocytes was studied. NKCF activity was generated in response to K562-inducer cells. The presence of NKCF in supernatants was always accompanied by antiviral activity, but in several experiments IFN was detected without concomitant NKCF. In no instance was NKCF activity detected in the absence of IFN. Cell lines which were good inducers of IFN-alpha were found to be good inducers of NKCF. NKCF activity of supernatants was completely adsorbed after incubation with MOLT-4 cells, whereas there was only minimal depletion of IFN-alpha activity. Most of the antiviral activity and all of the NKCF activity of preformed supernatants was neutralized by anti-IFN-alpha serum, whereas anti-IFN-gamma serum and pH2 inactivation had minimal effect on either activity. Addition of IFN-alpha to neutralized supernatants restored NKCF activity. These experiments support the hypothesis that IFN-alpha is involved in the modulation of NKCF-lytic activity. Both antiviral and NKCF activities were abrogated when anti-IFN-alpha serum was added to cultures of lymphocytes plus inducer cells (induction phase). The addition of purified IFN-alpha to such cultures was effective in allowing resumption of NKCF activity; however, addition of IFN-gamma to these cultures did not overcome this block. The addition of purified IFN-alpha directly to supernatants generated in the presence of anti-IFN-alpha serum could not restore their NKCF activity, thereby suggesting an additional requirement for IFN-alpha in the production of NKCF. The possible role of IFN-alpha in the generation of NKCF and expression of its lytic activity is discussed.

Natural cytotoxicity and interferon production in patients with recurrent respiratory papillomatosis.

The observation that interferon (IFN) therapy causes regression of lesions in some patients with recurrent respiratory papillomatosis (RRP) raises the possibilities that these patients may have abnormalities in endogenous IFN production or in antitumor immune responses stimulated by IFN. We have measured IFN production and natural cytotoxicity (NK activity) in nine patients with RRP, three of whom were receiving exogenous IFN at the time of testing. Production of IFN-gamma induced by the T cell mitogen Staphylococcus enterotoxin A was normal in all patients. Production of IFN-alpha induced by two viruses (Sendai and Newcastle disease viruses) was normal in the six untreated patients, but significantly lower in the patients on IFN therapy. Natural cytotoxicity against K562 target cells, both spontaneous and IFN-stimulated, was normal in all RRP patients tested. Thus, we have shown that the NK-IFN system was intact in untreated patients with RRP. IFN-alpha production in the RRP patients on IFN therapy was low. The significance of these findings is discussed.

Defective natural cytotoxicity in patients with cancer: normal number of effector cells but decreased recycling capacity in patients with advanced disease.

Patients with advanced cancer exhibited lower natural cytotoxicity against K562 target cells in a standard short-term chromium release assay than did patients with localized malignancy or normal individuals. Although natural killer (NK) activity of advanced cancer patients could be augmented by nylon column depletion of adherent cells and enriched further by fractionation of discontinuous Percoll gradients, the NK level attained remained below that obtained from PBL of normal donors treated by the same procedures. The pattern of NK activity obtained on the Percoll gradients was the same for all individuals studied. The proportion of large granular lymphocytes (LGL) paralleled NK activity and was highest in the peak NK fraction in all individuals tested. Advanced cancer patients with low NK activity showed no decrease in number of LGL from that of other cancer patients or normals. Similarly, there was no decrease in target binding cell number. Using a single-cell assay in agarose, we found that the number of active NK cells was the same for all patients, whether with localized or advanced malignancy, and normal subjects. In a 3-hr time period, there were no differences in the rate of killing in agarose. The maximum killing potential (Vmax) of the NK-deficient advanced cancer patients in a 51Cr-release assay was significantly lower than that of normals or other cancer patients. The observed defect in natural cytotoxicity of these patients thus appeared to be due to a reduced recycling capacity.

Natural cytotoxicity and interferon production in human cancer: deficient natural killer activity and normal interferon production in patients with advanced disease.

Natural cytotoxicity was measured in 51 adult patients with solid epithelial malignant tumors and in 27 normal subjects. Peripheral blood leukocytes (PBL) from 31% of the patients and 7% of the controls failed to kill target cells (K562) in a short-term chromium-release assay. When patients were classified according to clinical stage, PBL from 12% of patients with localized cancers, but 50% of patients with advanced disease, failed to exhibit cytotoxicity within the normal range. Pretreatment of PBL with interferon alpha (IFN alpha) or with Newcastle Disease Virus (NDV), a potent inducer of IFN alpha, enhanced cytotoxicity from all normal subjects. Of patients whose PBL lacked spontaneous cytotoxicity, half were able to kill normally after pretreatment of PBL with IFN alpha or NDV. Virtually all the patients whose PBL were unable to kill despite pretreatment with IFN alpha or virus had disseminated malignancies. IFN alpha production by PBL exposed to NDV and to K562 cells was normal in all the patients regardless of stage of disease or ability to kill K562 cells. The observed defect in natural cytotoxicity is thus unlikely to be due to a failure of PBL to produce IFN alpha.

Interferon as a mediator of human lymphocyte suppression.

Evidence is presented that interferon (IF) is a major mediator of the human concanavalin A (Con A) suppressor cell. The suppressive effects of Con A-activated lymphocytes on the mitogen responses of normal responder cells were largely abrogated by addition of anti-human leukocyte IF serum. Similar suppressor activity was generated by coculture of peripheral blood leukocytes (PBL) with a melanoma cell line (MeWo) and a HeLa cell line persistently infected with measles virus that induced the production of IF by lymphocytes. A human mammary carcinoma line (MCF-7) and two bladder carcinoma lines (T24 and TCCSUP) failed to induce IF or suppression. Addition of anti-human leukocyte IF serum to suppressor cells and supernates from tumor cell-lymphocyte cocultures largely abolished suppression and neutralized the antiviral activity of such supernates. Exposure of PBL from purified protein derivative (PPD)-positive donors to PPD caused the production of suppressor activity and IF. PBL from PPD-negative donors failed to produce significant amounts of IF or to suppress on exposure to PPD. Supernates from PBL treated with virus (Newcastle disease virus [NDV]) contained IF and suppressed the mitogen responses of responder PBL. Both the suppressive and the antiviral activities of this material were eliminated after treatment with anti-IF serum. To ascertain whether antiviral and suppressive activities were mediated by the same types of IF, supernates from PBL cultured with Con A, PPD, NDV, and tumor cells were treated with anti-IF serum or acid pH. In all cases antiviral activity was neutralized in parallel with abrogation of suppressor activity. These results provide strong evidence for the role of IF as a mediator of human suppressor cell activity.